After carefully reading the timeline, I think the most surprising part is that when Chrome switched again to defaulting to local time for date-only forms in 2015 (together with date-time form), someone complained it was a "breaking change", despite the fact that it was simply following the spec, and it even went so far that it eventually caused the spec itself to change, and now we’re stuck with the Frankenstein mess we have today.<p>By that, I don't mean to dismiss the importance of backward compatibility, but this case is particularly funny because:<p>1. It had already been changed multiple times, each a breaking change, so it’s not like this form of compatibility was ever seriously respected;<p>2. Having it behave differently from other "legacy forms," like the slash-separated version, is itself arguably a break in backward compatibility;<p>3. As noted in the article, it never worked the same between Chrome and Firefox (at this point) anyway, so it’s doubtful how impactful this "breaking change" really was, considering you already had to write shim code either way.